The present disclosure relates to a multilayer ceramic electronic component to be embedded in a board and a printed circuit board having a multilayer ceramic electronic component embedded therein.
As electronic circuits have become highly densified and highly integrated, a mounting space for passive elements mounted on a printed circuit board (PCB) has become insufficient, and in order to solve this defect, ongoing efforts have been made to implement components able to be installed within a board, i.e., embedded devices. In particular, various methods have been proposed for installing a multilayer ceramic electronic component used as a capacitive component within a board.
In one of a variety of methods of installing a multilayer ceramic electronic component within a board, the same dielectric material used for a multilayer ceramic electronic component is used as a material for a board and a copper wiring, or the like, is used as an electrode. Other methods for implementing a multilayer ceramic electronic component to be embedded in a board include a method of forming the multilayer ceramic electronic component to be embedded in the board by forming a polymer sheet having high-k dielectrics and a dielectric thin film within the board, a method of installing a multilayer ceramic electronic component within a board, and the like.
In general, a multilayer ceramic electronic component includes a plurality of dielectric layers formed of a ceramic material, and internal electrodes interposed between the dielectric layers. By disposing such a multilayer ceramic electronic component within a board, a multilayer ceramic electronic component to be embedded in a board having high capacitance may be implemented.
In order to manufacture a printed circuit board (PCB) including a multilayer ceramic electronic component embedded therein, a multilayer ceramic electronic component may be inserted into a core board, and via holes are required to be formed in an upper laminated plate and a lower laminated plate by using a laser in order to connect board wirings and external electrodes of the multilayer ceramic electronic component. Laser beam machining, however, considerably increases manufacturing costs of a PCB.
In a process of embedding the multilayer ceramic electronic component in the board, a heat treatment process for curing an epoxy resin and crystallizing a metal electrode is performed. In this case, a difference in coefficients of thermal expansion (CTE) between the epoxy resin, the metal electrode, a ceramic of the multilayer ceramic electronic component, and the like, or a defect in an adhesion surface between the board and the multilayer ceramic electronic component due to thermal expansion of the board may occur. This defect causes delamination of the adhesion surface in a reliability test process.
Meanwhile, in the case in which a multilayer ceramic capacitor is used as a decoupling capacitor of an application processor of a smart phone or a high performance integrated circuit (IC) power supply terminal of a personal computer (PC), such as a central processing unit (CPU), when an equivalent series inductance (hereinafter, referred to as an “ESL”) increases, performance of an IC may be deteriorated. As performance of the application processor of the smart phone or the CPU of the PC is gradually improved, an influence of the increase in the ESL of the multilayer ceramic capacitor on the deterioration of the performance of the IC relatively increases.
A “low inductance chip capacitor (LICC)” is intended to decrease a distance between the capacitor and an external terminal to decrease a path of a current flow, thereby decreasing an inductance of a capacitor.
Also in the case of the multilayer ceramic electronic component to be embedded in a board, the “LICC” needs to be applied in order to decrease the inductance as described above.
However, in the “LICC”, it is difficult to implement bandwidths of external electrodes in the same level as those of a general multilayer ceramic electronic component to be embedded in a board.
Therefore, in the case of applying the “LICC” to the multilayer ceramic electronic component to be embedded in a board, a processing area of vias for electrical connection with a package substrate circuit decreases, such that it is difficult to embed the “LICC” in the board.
In addition, external electrodes of the multilayer ceramic electronic component to be embedded in a board are generally formed by applying conductive pastes for the external electrode to both end portions of a ceramic body.
In this case, due to bleeding of the conductive pastes for the external electrode applied to upper and lower surfaces of the ceramic body, a deviation between bandwidths of the external electrodes occurs, such that a defect may frequently occur at the time of processing the vias.
In addition, in the case in which the deviation between bandwidths of the external electrodes occurs as described above, connection between a plurality of vias is impossible, such that it is difficult to decrease a current path in order to decrease an ESL.